Optical fiber is increasingly being used for a variety of broadband applications including voice, video and data transmissions. As a result, there is a need for connecting remote locations to a fiber optic distribution cable in order to provide broadband services to an end user, commonly referred to as a subscriber. In this regard, fiber optic networks are being developed that deliver “fiber-to-the-curb” (FTTC), “fiber-to-the-business” (FTTB), “fiber-to-the-home” (FTTH) and “fiber-to-the-premises” (FTTP), referred to generically as “FTTx.” networks. To provide these services to the subscriber, FTTx networks include a large number of interconnection points, referred to herein as “tap points,” at which one or more optical fibers of a distribution cable are interconnected or mated to optical fibers of one or more cables leading to a subscriber location. In addition, in order to reduce installation labor costs in FTTx networks, communications service providers are increasingly demanding factory-prepared interconnection solutions, commonly referred to as “plug-and-play” systems.
To supply the large number of tap points needed and to satisfy the demand for plug-and-play systems, it is apparent that more efficient methods of providing mid-span access locations along the length of a distribution cable are needed. Typically, to perform a mid-span access of a distribution cable, a field technician first removes a section of the cable sheath at a convenient location along an installed distribution cable. Once the sheath is removed, the technician gains access to one or more optical fibers through the cable sheath, severs the accessed optical fibers and withdraws a length of the severed (or “terminated”) optical fibers from the distribution cable. The length of the terminated optical fibers provides the field technician with the ability to splice one or more optical fibers of a cable comprising a lesser amount of optical fibers than the distribution cable (typically referred to as a “tether”) to the terminated optical fibers of the distribution cable. Often an excess fiber length (EFL) or excess ribbon length (ERL) of the distribution optical fibers must be loaded into the tether or some other type of accumulation section. After splicing is completed, the mid-span access location is typically covered using an enclosure designed to protect the splices (which are external to the jacket of the distribution cable) and the exposed section of the distribution cable. This time-consuming process is typically accomplished by a highly skilled field technician at a significant cost and under less than ideal working conditions.
Several approaches have been developed to overcome the disadvantages of accessing, terminating and splicing optical fibers in the field. In one approach, the splicing of a tether to the distribution cable is performed at a factory during the manufacturing of the cable. The preterminated distribution cable, including the main cable, tether and associated splice closures, are assembled and wound onto a cable reel to be delivered to an installation site. Accordingly, favorable conditions in the factory for making high quality splices may be utilized, thereby increasing splice quality and also reducing the expense, difficulty and unfavorable conditions associated with splicing in the field. One disadvantage of this approach is that the tethers and splice closures are relatively bulky. For example, large enclosures are typically used to protect the splices and the section of the distribution cable that must be exposed to access the appropriate optical fibers to create the splices. In addition, the ERL/EFL of the distribution optical fiber can also lead to increased size of the tethers and/or splice closures. Accordingly, installation through small diameter conduits and over sheave wheels and pulleys is substantially more difficult, and sometimes impossible.
Therefore, it would be desirable to provide a factory-assembled fiber optic distribution cable having one or more predetermined mid-span access locations along the length of the distribution cable wherein each such mid-span access location has a tether connected directly thereto that does not have the bulk of traditional tethers and/or splice closures. It would also be desirable to provide a distribution cable in which the splices are in the interior of the distribution cable.